Patent Document 1 discloses a battery assembly configured such that a plurality of electric cells aligned in one row are sandwiched and fixed by a pair of side plates located at both ends in the alignment direction.
Patent Document 2 discloses a battery assembly configured such that a plurality of electric cells are aligned in a case having a box shape and open upper end and the opening of the case is closed by a cover.
In the configuration according to Patent Document 1, the number of the electric cells in the alignment direction can be increased and decreased by relatively easy redesign. Other than the above, change in arrangement of the electric cells requires significant redesign. In the configuration according to Patent Document 2, it is necessary to redesign both the case and the cover in order to change the arrangement of the electric cells. Each of the case and the cover is typically made of a resin. It is thus necessary to prepare new expensive molds for shaping the case and the cover due to such redesign. As described above, the battery assemblies according to Patent Documents 1 and 2 each have the low degree of freedom of the arrangement of the electric cells in view of the restriction in cost. It is thus difficult to achieve various kinds of small quantity production at a low cost.
Patent Document 3 discloses a battery assembly in which each of rectangular electric cells is provided at both sides thereof with protrusions and a through hole is provided at each of a pair of exterior plates laterally sandwiching the electric cells. Vibration proof and impact resistance are improved by fitting the protrusions to the through holes.
In order to assemble the battery assembly according to Patent Document 3, after the plurality of electric cells are aligned, the electric cells need to be laterally sandwiched by the pair of exterior plates in a state where the through holes are accurately positioned at the protrusions provided at the both sides of the electric cells. In this regard, the battery assembly according to Patent Document 3 requires complicated assembly work with less easiness.